Surgical Management of Congenital Pulmonary Airway Malformations (CPAM) in an Infant and a Toddler: Case Report Depicting Two Distinct Surgical Techniques With Successful Outcomes

Congenital pulmonary airway malformations (CPAM) compose the major part of congenital lung malformations (CLM) and have traditionally been treated by pulmonary lobectomy. In terms of surgical strategy, lobectomy has conventionally been the preferred treatment for CPAM localized to a single lobe. More recently, alternative approaches including lung-sparing resections (LSR), such as wedge or non-anatomic resections and segmentectomy, have been suggested. In asymptomatic CPAM early surgical resection is often shown to reduce infection and malignancy development. We describe two patients who were diagnosed with CPAM when being evaluated for respiratory tract infection. Patient 1 (P1) was a two-month-old infant weighing 4 kg with glucose-6-phosphate dehydrogenase (G6PD) deficiency and Patient 2 (P2) was a toddler aged one year, nine months weighing 9 kg. P1 underwent LSR for the CPAM diagnosed in the left upper lobe of the lung with conventional mechanical ventilation whilst right upper lobectomy was performed in P2 using one/single lung ventilation. In both cases, LSR and right upper lobectomy led to an uneventful postoperative recovery with no complications reported.


Introduction
Congenital pulmonary airway malformations (CPAM) constitute the core of congenital lung malformations (CLM).In this condition, there is excessive proliferation of the respiratory tree leading to an abnormal bulk of tissue and resulting in anomalous alveoli development [1].The actual incidence remains uncertain, with prior approximations varying from 1:11,000 to 1:35,000 live births, but current indications suggest it is approximately 1:7,200.Studies have indicated male predominance in lesions appearing during early infancy.Advancements in prenatal ultrasound methodologies, increased accessibility to prenatal therapies and interventions for fetal issues, and improvements in neonatal intensive care have all contributed to progress in perinatal healthcare and possibly to the increase in the reported incidences [2].
While the exact origin of CPAM remains uncertain, it is believed to stem from hamartomatous malformation and excessive pulmonary tissue proliferation at different locations [3].The Stocker's classification uses the diameter of the cyst and location to categorize CPAM into five main types (Type 0 to Type 4) according to histopathological criteria [4].As the patient had persistent requirement for ventilatory support and respiratory distress, high resolution contrast-enhanced computed tomography chest (HRCECT) was done which revealed presence of Type I CPAM.

Case 2 (P₂)
The second patient is a one-year, nine-month-old toddler weighing 9 kg born full term via vaginal delivery and having history of neonatal jaundice requiring phototherapy and presented with respiratory tract infection and slowly progressive protrusion of lower part of sternum.CXR was done to rule out any abnormality and revealed a large radiolucent shadow in the right lung.Further evaluation via imaging showed Type I CPAM in the right upper lobe of the lung (Figure 2).

Anesthesia protocol
The induction of anesthesia is very crucial during the surgery of CLM.In P1, a single lumen endotracheal tube was used for tracheal intubation.In P2 one-lung ventilation (OLV) using Arndt Pediatric Endobronchial Blocker 5 Fr.(Cook Medical, Bloomington, IN, USA) was adopted (Figure 3).The specimen delivered in both cases were sent for histopathological examination and staining methods were used for demonstration of the cyst wall (Figure 7).

Results
Both cases had an uneventful recovery with no complications.A follow-up CECT scan was done at one month post-discharge which revealed no residual lesions (Figure 8, Table 2).

Discussion
The range of CLM alternatively known as congenital thoracic malformations, includes diverse conditions like CCAM, congenital lobar emphysema, bronchial atresia with distal cystic degeneration, bronchopulmonary sequestration, bronchogenic and foregut cysts.Although these anomalies may be detected in prenatal assessments, a conclusive diagnosis necessitates histological examination [6,7].
The current treatment scheme indicates that surgical management is essential for alleviating postnatal symptomatic lesions including spontaneous pneumothorax, recurrent infection, hyperinflation, left-to-right shunting, and pulmonary hypoplasia caused by a large mass [8].Conversely, managing asymptomatic lung lesions is a subject of controversy due to concerns about overall complications and the uncertain long-term outcomes due to a lack of follow-up [9][10][11].
Advancements in prenatal imaging have heightened the therapeutic challenges in dealing with these infants.The decision-making process is increasingly complex due to the heightened risk of complications associated with CCAM, including respiratory failure, recurrent respiratory tract infections, airway obstruction, and the potential for malignant transformation (bronchioloalveolar carcinoma, rhabdomyosarcoma, pleuropulmonary blastoma) [11,12].These factors have now become the main criteria for considering surgical resection.
CPAM make up 95% of congenital cystic lung diseases.Prenatal screening ultrasound done at 18 -20 weeks of gestation has shown cystic lung lesion to be the commonly observed anomaly.The documented prevalence of CPAM is roughly 1 per 25,000-35,000 live births [13].The specific CPAM type reflects the development of abnormalities across the tracheo-bronchial tree (Table 3, Figure 9).

Sr.
No.   Fetal therapy has gained popularity owing to its high success rate in the last decade.The current prenatal treatments are described in Figure 10.Moreover, neonates exhibiting this anomaly typically manifest respiratory difficulties and experience recurrent infectious diseases [16].The surgical handling of asymptomatic CPAM remains a contentious topic within the realm of pediatric thoracic surgery.Despite numerous investigations, a clear delineation of the optimal timing for surgical intervention and the specific resection procedures has yet to be established.
In our case, patient P1 underwent LSR of the left upper lobe of the lung at two months of age.Concerning the surgical strategy, lobectomy has traditionally been the preferred treatment for CPAM limited to a single lobe.Recently, alternative procedures known as LSR, including segmentectomy and non-anatomic resections like wedge resections, have been suggested [17].The primary goal of LSR is to retain a significant portion of the lung tissue.Initially applied in cases with multiple lobes affected, certain medical teams have gradually expanded its usage to include a majority of cases, especially for the smallest and most peripheral lesions.In the other case, patient P2 underwent right upper lobectomy at one year, nine months.
While there is widespread agreement on neonatal surgery, concerns have been raised in various reports regarding surgical procedures in infants.The rationale behind advocating surgery for asymptomatic patients with CPAM during infancy lies in the prevention of bacterial dissemination and the potential malignization of cystic wall.It is suggested that asymptomatic infants undergo surgery after reaching one year of age to ensure proper growth [18].
However, conflicting recommendations exist, with some studies proposing earlier surgical interventions than the aforementioned guideline [19,20].For instance, Style et al. found that patients having surgery at an age less than or equal to four months experienced shorter operative times and anesthesia durations compared to those undergoing late resection (more than four months) [19].
The natural progression of unresected CPAM remains uncertain, as some studies indicate that certain cases may remain asymptomatic for extended periods [9].Additionally, prior literature has highlighted a paradoxical increase in infections following surgical resection [21].

FIGURE 2 :
FIGURE 2: Case 1 (P1) (a) CECT scan of chest axial section in lung window (section 1) at the level of upper lobe showing a well-defined, thin-walled air containing cystic cavity lesion with surrounding lung parenchyma shows changes of passive collapse in left lung upper lobe.(b) CECT of section 1 in mediastinal window at level of upper lobe showing well-defined air-containing cavernous lesion with thin wall on CECT scan.(c) CECT of chest sagittal section in lung window showing air containing well-defined cystic lesion noted in left upper lobe with adjacent areas of collapse and left oblique fissure which separate left upper and lower lobe.(d) CECT of (section 1) in lung window at level of upper lobe showing a well-defined air-containing cavernous lesion in left upper lobe with upper lobar subsegmental bronchus appear in direct contact with cystic lesion and adjacent areas of passive collapse.(e) CECT of (section 1) showing well-defined air-containing cystic lesion

FIGURE 7 :
FIGURE 7: Case 1 (a) Scanner view (4x magnification, H&E stain) showing fibro-collagenous cyst wall, lined by flattened epithelium (i), cyst cavity contains granulation tissue comprised of fibrous tissue, congested blood vessels, inflammatory cells (ii), (b) Low power view (10x magnification) shows adjacent alveolar tissue forming small, irregularly shaped airway spaces (i), lined by ciliated, cuboidal to columnar epithelium.The septa appear thickened and septal spaces appear dilated at places.Immature cartilage (ii) and bronchial glands (iii) are seen within the cyst wall, (c) High power view (40x magnification, H&E stain).Clusters of foamy macrophages and pneumocytes with vacuolated cytoplasm (arrows), Case 2 (d) Right side shows heavily congested lung parenchyma with collapsed alveoli (i), Left side shows adjacent lung tissue with mild congestion and focal alveolar enlargement (ii).H&E -Hematoxylin and Eosin; P -Patient Image Credit: Dr. Zalak N. Parmar

FIGURE 8 :
FIGURE 8: Case 1 (a) HRCT Axial scan chest in mediastinal window, (b) Coronal HRCT scan chest in lung window showing areas of collapse with atelectasis noted in apico-posterior and anterior segments of left upper lobe with mild volume loss of left upper lobe with mild upward displacement of left oblique fissure.Case 2 (c) Postoperative axial HRCT scan of chest in mediastinal window showing mild fluid density areas with internal few small air foci noted in apical and anterior area adjacent to first and second intercostal space right side.There are few internal radiopaque surgical clips noted, (d) Postoperative coronal HRCT scan of chest in lung window showing stapler occluding right upper lobar bronchus.There are areas of adjacent sub-segmental collapse noted.

Figure 11
illustrates the algorithm for surgical indications in CPAM.Pankhaniya, Swati M. Kamani, Gaurav D. Bhoraniya, Dharmendra B. Parmar, Roshni A. Purswani, Alpa M. Patel, Nili J. Mehta, Kartik B. Dhami, Zalak N. Parmar, Haryax V. Pathak, Vrajana J. Parikh, Rushi B. Barot, Deepali M. Shah, Amit Kumar, Ashwin S. Sharma, Sohilkhan R. Pathan Disclosures Human subjects: Consent was obtained or waived by all participants in this study.Institutional Ethics Committee (IEC-2), HM Patel Centre for Medical Care and Education, Anand, Gujarat issued approval Approval No. IEC/BU/2023/Cr.43/365/2023 dated 04/12/2023.Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work.Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work.Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.

TABLE 1 : Patient Characteristics
P -Patient